thank you xxgtrguyxx for your input, I have done a bit of research on the subject and come to a figure that i thought the car is worth.
Looking at other 94 R32 GTR V-Spec II's that are for sale the asking price is generally around $29-30k. From there i factored in that gtr's with forged rebuilds are generally $5-8k more than a stock standard ones. Then i have an $8k stereo and a $2k alarm, i also have all the old parts taken from the car that will be included in case the new owner wanted to return it to stock as well as an excellent service history with lots of documents to back it up.
considering that its around a $30,000 car and i've spent over $15,000 just on parts for a rebuild on it, an asking price of around $39,000 seems pretty good... you are getting over $35,000 worth of rebuild work completed this year and an $8,000 stereo for about, well, lets say $10,000. AND this is just after the run in has been completed - its basically a new car mechanically!
If this seems unfair to you, i'm sorry, but i think (and i hope there would be others who would agree with me) that its actually quite fair